Dressing



0d. 1956 w. c. SKILES, JR., EFAL 2,764,976

. DRESSING Filed Jan. 10, 1955 HENRY/.- .450

5) ATTaR DRESSiNG William C. Skiles, In, Milltown, Joseph N. Masci,Metuchen, and Henry F. Maso, New Brunswick, N. J assignors to Johnson &"Johnson, a corporation of New Jersey Application January 10, .1955,Serial No. 480,674

-I-9 Claims. (Cl. 128-1 5 6) This invention relates to surgicaldressings and, in particular, to dressings impregnated with an oilcomposition to impart improved therapeutic properties to the dressing.

Ordinarysurgical dressings, when left in contact with'a wound, willadhere firmly in a relatively short time. This is primarily due to thefact that blood and'serous exudates -form a coagulum which enmeshes thefabric threads'of the dressing and, being firmly adherent to the surfaceof the wound, binds the dressing to it very firmly. Secondly, indressings which must be left in contact with a wound for prolongedperiods there is danger that granulation tissue -will actually growinto'and adhere to the dressing.

Removal of adherent dressings 'is 'difiicult and painful, and tends tocause further damage to tissue.

'It has been known to impregnate dressings with ordinary petrolatum inan attempt to increase non-stic'lring and other therapeutic propertiesof the dressing. However, a disadvantage of such dressings is that theytend to dam up fluid exudate, 'tlrere'by'produ'cing maceration of thetissue.

Further, a serious disadvantage of prior art dressings is theextrernedifii'culty in sterilizing the dressings. In fact, it has been necessaryto sterilize the gauze 'or other dressing material, separately sterilizethe impregnant, and then combine the two, using aseptic technique. Thisprocedure is manifestly cumbersome, expensive and diflicult to control.Further, the elevated temperatures necessary to sterilize the anhydrousimpregnant, such as petrolatu'm, cause deterioration 'or decompositionof many desirable .me'dicinals. that may be incorporated therein.

zable using a time cycle and temperauire not substantially difierentfrom those used in conventional steam steriliia tion procedures.

A preferred object and advantage lies in an-impfoved dressingincorporating desirable medicinals the utility of which in the past hasbeen limited by elevated'temperatures necessary for sterilization ofprior art dressings.

-A particular. object of the invention is to prepare a dressing havinglittle or no tendency to fray or shed loose threads, even when out onthe bias. I g

A further particular object of the invention is to prepare a surgicaldressing having one or more of the reregoing properties and furtherhaving the ability to be stretched substantially in the lateral or crossdirection with minimum tendency to stretch on the longitudinal dimensionof the dressing.

The dressingof the present invention comprises a hacking of open meshfabric having regularly spaced openings of acertain size describedhereinafter, impregnated with particularamounts of an oil containingcertain othermaiteatent "rialsalso'described below, which materials areimportant "in producin the desired objects or the invention.

"tend to permit projection of fibers from superposed ab- 'sorbentdre'ssings through the openings and adherence of solidified exudate tothe fabric threads; so average -open- 'i'ng size is maintained less thanabout 0.04 'sqiin. Con- 'v'ersely, extremely small openings tend toproduce inaeeration'of underlying wou'n-d tissue; so aver-age area ofthe openings is greater than about 000015 sq. in.

Preferred average opening size is about 0.00035 sq. in.

Which' approximates the size for standard surgical gauze having a thread'count of approximately '44 x '36. The types of meshes which may be usedin the fabric are descr'ibe'd ingreater detail below.

The impregnant is an 'oil with emulsifying agent or a'gents dispersedtherein. This oil composition is present on the fabric in amountsufiicient to prevent the fibers from sticking to the wound. The oilsemployed have the inherent property of making coagulum of wounde'xudates adhere only slightly to the threads of the dressing. The

wetting agents promote rapid 'wicking of wound exudation through theimpregnated dressings and into seconnary dressings of standard absorbenttype. This prevents damming of fluids, maceration of the wound, andprevents the dressing from being engulfed by coa g ultltn which wouldcause the 'dressihg to Stick to the wound. To achieve the desiredobjectives, the amout of oil present in the oil composition in thedressing is at least about 5 based on the dry weight of dressing.

-It has been a common fault of the prior dressings that excessiveamounts of oil were used, thereby seriously interfering with the escapeof body fluids from the wound through the dressing immediately incontact therewith and into absorbent layers or regions on the oppositeside of the impregnated dressing. According to the present invention,the amount otoil composition is controlled within a minimum amountneeded to impart the desired non sticking properties to the fabric, anda maximum amount beyond whichthere is found excessive dammin'g of fluidexudates. A major proportion of fabric openings is thereby left open forpassage of fluid. Within the broader scope of the'invent-ion, amounts ofoil'composition based on dry'weight of fabric within the approximaterange 20% to 200% are contemplated. Preferred'objects from thestandpoint of non-sticking properties consistent with negativemaceration are realized Within the approximate range to by weight of oilcomposition based on the dry fabric.

As indicatedabove, the diiiiculties in sterilizing prior art petrolatumdressings arise from the practical impossibilityof permeating ordinarypetrolatum with moisture. According to the present invention, therefore,there is uniformly dispersed in the petrolatum or other oil describedhereinafter a certain amount of finely divided water which isnecess'arto bring about sterilization of the composition under conditions ofelevated temperature ordinarily maintained in steam sterilizationprocedures. From this standpoint, the amount of Water present is atleast about 4% based on the weight of the oil composition. Largeramounts may be employed, if desired, as will appear from the examplesgiven below. Although Water-ih-oil emulsions have been indicated and areprenut, corn or almond oil.

ferred, certain advantages of the invention may be realized by use ofoil-in-Water emulsions.

Petrolatum or other mineral oil is a particular type of oil foundsuitable for purposes of the present invention. However, bland non-tonicvegetable oils may alternatively be employed. Examples of such oils arepeanut, cocoa- Animal fats and oils are suitable, such as tallow, woolgrease, and whale oil. Hydrogenated vegetable oils and fats are alsosatisfactory.

Silicone oils, i. e. polysiloxanes having viscosity from about 40centistokes at 33 C. to 100,000 centistokes at 25 C., with suitablewetting agents, may be used and objects and advantages of the inventionrealized.

A primary function of the wetting or emulsifying agent, as aforesaid, isto impart wettability to the impregnant and thereby minimize thetendency to dam fluids adjacent the body and produce maceration. Thewetting agents also facilitate irrigation of the wound and removal ofany portions of the oil composition which may have adiered thereto.Preferably, two types of emulsifiers are employed: first, an oil-solubleemulsifier which expedites wound drainage as described above; and,second, a watersoluble emulsifier. In some instances both types aremixed in a single composition sold in commerce. Although two emulsifiersmay be used, a single emulsifier incorporating the properties of bothmay be substituted. Satisfactory oil-soluble emulsifiers includesorbitan sesquiolcate sold under the trademark Arlacel C. This typedissolves in the oil phase and increases its hydrophilic properties.Partial esters of fatty acids and polyhydric alcohols, such as glycerylmonostearate, are suitable. Lanolin is another example. Fatty alcohols,fatty acids, fatty acid amides and similar agents may also be emloyed.

The water-soluble emulsifiers contribute to the wettability of thefabric. Their principal function is in forming an emulsion of the oilwith Water so that the dressing may be readily sterilized. A suitablematerial is the polyoxyethylene derivative of sorbitan monooleate soldin cornmerce under the trademark Tween 80. sorbitol derivative, amannitol derivative may be stituted; instead of polyoxyethylenederivative, a polypropylene derivative may be substituted; and insteadof oleate, a similar derivative of other high molecular weight fattyacid may be substituted. Other suitable emulsifiers known in the art maybe substituted.

It will now be apparent that each of the emulsifiers is used in amountsufficient to produce the desired emulsifying effect. According to theinvention, at least about 2% total emulsifier (1% of each of thewater-soluble and oilsoluble emulsifiers) is used based on the totalweight of the oil composition. Preferably, at least about 2% or each ofthe two types is present.

Certain features of the invention may be understood by reference to theattached drawing.

Fig. l is a detail view on an enlarged scale of a fabric according toone embodiment of the invention impregnoted with an oil composition. Theknit chains are shown enlarged in proportion to the rest of the fabric.

Fig. 2 illustrates the dressing of Fig. 1 on a smaller scale and isintended to demonstrate the reaction of the material to lateral stress.

Fig. 3 shows a dressing incorporating a different type open-mesh fabric.

Fig. 4 is a sectional view of a wound and dressings ap plied thereto.

Fig. 5 is an isometric view of an adhesive bandage having a dressing padaccording to the invention.

Referring to Fig. 1, reference number indicates a series of parallelchains formed on conventional warp knitting equipment. Each chain 10 isformed of a series of needle loops i1 drawn one through the other insuccession. Floats or ties 12 connect the end of one needle loop withthe beginning of the next. Each row of simultaneously formed andoppositely disposed needle loops in Instead of the the cross directionof the fabric is designated by the term course. That is, in Fig. 1 thereare shown five courses of needle loops. It will be noted that each ofthe needle loops of Fig. l is formed in the same direction, that is, bymovement of the thread from left to right over the needle. However, thisis not limiting. If desired, the fabric may be formed by first movingthe threads from right to left across the needle in one course and inthe opposite direction, i. e. from left to right in the succeedingcourse, and so on.

Sinuous fill threads are indicated at 15. The fill threads 15 are loopedbetween different chains in the fabric, the loops being formed around alink of one of the chains and then around a link of another of thechains, each loop 16 of each fill thread 15 being in a course differentfrom the course in which the other loopings thereof occur. In the Fig. 1construction the fill thread, after looping itself around the link inone chain, moves over to the link in the next course of the adjoiningchain, and then back to the first chain two courses removed from theprevious link in the first chain. It will be noted further that, movingfrom the bottom to the top of the drawing, the leading part17 of eachthread loop 16 is bound in between a thread loop and a float of thatcourse. Following part 18 of the same thread loop is bound in betweenthe thread loop or" the following course in the same chain. The focalpoint of action of thread loop 16 on a chain is, therefore, the point 20at which two chain loops meet.

As the fabric, for example in Fig. 1, is stretched walewise, the chainloop knots tend to tighten and are relatively inentensible. This makesthe fabric more manageable. However, if the fabric is stretched in thecrosswise direction, the thread loops which point to the right will tendto distort the focal points 20 between adjacent chain loops to the left.The thread loops which point to the left, however, will act upon focalchain points 21 one course removed from focal points 20 so as to urgepoints 2i in the same course the entire width of the fabric toward theright. Any given chain, therefore, will be distorted in a zigzagfashion, first to the left by the loops pointing to the right in onecourse, farther on to the right by the thread loops pointing to theleft. The over-all effect will be a stretching of the fabric widthwiseand some contraction lengthwise, as shown in Fig. 2. This is also anadvantage since it makes the dressing readily conformable to irregularbody contours.

One significant advantage of the invention arises by reason of the factthat the fill threads 15 are bound in by the chains as described above.When the fabric is cut, whether longitudinally, transversely ordiagonally, ravelling such as is characteristic of woven or usuallyknitted goods will be minimized or entirely absent due to thisbinding-in feature.

The number of chains or wales 10 per inch width of the fabric, thespacing of the fill threads 15 and the diameter of the threads arecontrolled or chosen so as to produce an open-mesh fabric havingregularly spaced openings of size described above.

' The oil impregnant is indicated at disposed in such a fashion andaccording to the specifications set forth above so that the majorportion of openings 13 remain free.

Fig. 3 illustrates a dressing having a fabric of ordinary woven surgicalgauze of warp threads 36 and fill threads 37 interwoven with each other.The mesh of the gauze may suitably be 44 x 36. The oil impregnant isshown at 40 and is so disposed, as indicated above, that the majorportion of openings 41 remain free. A non-woven fabric conforming to theabove specifications may be used.

In Fig. 4, an invention dressing is shown applied to wound 61, withabsorbent material, such as cotton 62 on the opposite side. According tothe invention, the size of openings and the amount of oil compositionused is such that exudate from the wound passes-through dressing 60 intolayer 62, but dressing 60 does not *stick to the Wound, nor do thefibers from62 project substantially throughthe openings of dressing 60.

In Fig. 5, there is shown an adhesive bandage havinga conventionaladhesive-coated backing strip 70. The dressing pad "71 has a top layerof gauze 72, preferably 44 x 36 gauze, impregnated with an oilcomposition as described above to impart non-sticking properties.Preferably, an unimpregnated, absorbent sheet is disposed underneathimpregnated layer '72 to'absorb exudate transmitted through the latter.in use, the pad is placed in contact with the wound and the adhesivetabs are secured to adjacent portions of the The dressing may beprepared by warming together the oil and emulsifying agent to anelevated temperature, for example about 70 C. The Water is warmed tothesame temperature and is added slowly while agitating the mix to forma finely divided dispersion of the water in the oil phase. A controlledquantity of this preparation then may be impregnated on an open-meshfabric by either saturation of the fabric followed by a wringing-out ofexcess emulsion between squeeze rollers, or by direct application of theoil composition to the-fabric by means of printing or roller coatingtechniques.

The dressing may be packaged between layersof plasticcoated foil withthe plastic-coated surfaces adjacent each other, to form a heat-sealedbond. Sterilization may be effected by subjecting the sealed packages toa temperature of 240 F. for 30 minutes. If foilpackages are utilized,sterilization may be carried out according'to the procedure described inMasci U. S. P. 2,478,931 of August 16, 1949, to prevent undue distortion.of the package. Rigid-walled containers for the dressing of theinvention may be utilized if desired.

The following examples are presented as illustrating .the invention butnot in a limiting sense.

Example I An emulsion having the following composition was preparedaccording to the procedure describ d above:

The emulsion was spread on 44 x 36 gauze, which was woven of threadshaving 6 mils diameter, in the amount about 1.0 to 1.3 times the gauzeweight. Care wastaken that the mesh openings of the gauze were notfilled snb- .stantially by the impregnant. The dressing wassealed-between layers of foil and sterilized according to the proceduredescribed in Masci U. S. P. 2,478,931 by sub jecting it to temperatureof 240 F. for .30 minutes. It was found to be sterile. The sterilematerial was used in clinical tests on traumatized tissue and found tobe substantially free of sticking to the wound. Little or no macerationof the tissue was apparent during the clinical test.

Example 11 An emulsion having the following composition was preparedaccording to the procedure described above:

Percent U. S. P. white petrolatum 80.0 Sorbitan sesquioleate 4.9Polyoxyethylene sorbitan monooleate 4.9 Water 10.2

of the weight of the fabric and was so disposed as not to fill-theopenings. The dressing was sterilized in a'hermetically sealed packageby subjecting it to temperature of 240'F. for 30 minutes. 'The dressingwas sterile. It was found in clinicalntests to have minimum tendency tostick tothe wound. 'It produced no maceration.

Exampleilll The following emulsion was prepared according to theprocedure described above:

Percent Cetyl alcohol--- 3.0 Stearyl alcohol 3.0 'Stear'ic acid 3.0Mineral oil 5.5 Glycerol monostearate (self-emulsifying) 4.5 Water 8.1.0

The glycerol monostearate contained substantial amounts of potassiumstearate :soap which made the material selfemulsifying. The emulsion wasspread on 28 x 24 gauze in amount of about 175% of the weight of thegauze. The impregnated gauze was packaged and sterilized according tothe procedure described in Masci Examples 1 and 2.

It waslater clinically tested and found to have minimum tendency tostick to'wounds and no tendency to produce maceration.

Example IV An emulsion having the following composition was prepared:

. Percent Glycerol monostearate (self-emulsifying) 6. 5 Peanut oil 62.10Water 31.5

Example -V The following oil composition-was prepared:

Petrolatum? parts by weight ,Sorbitan sesquioleate parts 4.9'Polyoxyethylene sorbitan monooleate do 4.9

The petrolatum and the other materials were warmed and stirred togetherat about 70 C. thereby to effect a uniform dispersion. The dispersionmaybe sterilized by application of heat at about C. for 10 hours. 44 x36 gauze is sterilized separately and is coated with thesterilizedemulsion using aseptic technique. An .aluminum foil package is similarlysterilized and is loaded "with the impregnated gauze using aseptictechnique. The amount of emulsion on the gauze is about 1.0 to 1.3 timesthe gauze weight. The dressing, when used in contact with a wound willbe found to have outstanding nonsticking and non-maceration properties.

Example VI An emulsion having the following composition is pre- Theemulsion was spread on 44 x 36 gauze to the extent of about of the gaugeweight. It was hermetically sealed in a package and sterilized byheating to a temperature of 240 F. for 30 minutes. The sterilizeddressing was found to have excellent non-sticking and non-macerationproperties in contact with the wound.

Although specific embodiments have been described in the foregoingspecification, it is understood that this presentation is made in anillustrative and not a limiting sense. Accordingly, it is intended tocover in the appended claims all modifications and equivalents withinthe spirit of the invention.

The claims are:

l. A surgical dressing comprising an open mesh base fabric impregnatedwith an oil composition, said fabric having regularly spaced openings ofaverage area'in the approximate range 0.00015 to 0.04 sq. in. each, saidoil composition comprising at least by Weight of a bland non-toxic oilbased on the dry weight of fabric and 2% of wetting agent based on thecomposition, the amount of said composition being in the approximaterange 20 to 200% of the dry weight of the fabric.

2. A dressing according to claim 1 having at least 1% of an oil-solublewetting agent and at least 1% of a water-soluble wetting agent.

3. A dressing according to claim 2 having at least 2% each ofoil-soluble and Water-soluble wetting agents.

4. A dressing according to claim 1 in which the amount of saidcomposition is in the approximate range 100-160% of the dry weight ofthe fabric.

5. A surgical dressing comprising an open mesh base fabric impregnatedwith an oil and Water emulsion, said fabric having regularly spacedopenings of average area in the approximate range 0.00015 to 0.04 sq.in. each, said emulsion comprising at least 5% by weight of a blandnon-toxic oil based on the dry weight of fabric, and 2% oil solublewetting agent, 2% water-soluble wetting agent, and at least 4% water,each based on the emulsion, the amount of said emulsion being in theapproximate range 20 to 200% of the dry weight of the fabric.

6. A dressing according to claim 5 in which the amount of said emulsionis in the approximate range 100-160% of the dry weight of the fabric.

7. A dressing according to claim 6 in which the oil is a petroleum oiland the fabric is approximately 44 x 36 cotton gauze.

8. A sterilized dressing according to claim 7.

9. An adhesive bandage having a pad comprising a surface layer ofdressing material according to claim 8.

10. An adhesive bandage according to claim 9'in which said pad comprisesa layer of absorbent material beneath and adjacent said surface layer.

11. A surgical dressing comprising an open mesh base fabric impregnatedwith an oil and Water emulsion, said fabric comprising a base warp knitmaterial composed of walewise parallel chains and filling threads havingsinuous configuration looped between said chains, said fill thread loopsbeing formed around a link of one of said chains and then around a linkof another of said chains, each loop of each fill thread being in acourse different from the course in which the other loopings thereofoccur and the loops of different fill threads in the same coursepointing in the same direction, said fabric being substantiallyunstretehable in the walewise direction, but substantially stretchablein the direction normal thereto, said fabric having regularlyspacedopenings of average area in the approximate range 0.00015 to 0.04sq. in. each, said emulsion comprising at least 5% by weight of a blandnontoxic oil based on the dry weight of fabric, and 2% of oil-solublewetting agent, 2% water-soluble wetting agent, and at least 4% water,each based on the emulsion, the amount of said emulsion being in theapproximate range 20 to 200% of the dry weight of the fabric.

12. A dressing according to claim 11 in which the emulsion is awater-in-oil emulsion.

13. A dressing according to claim 11 in which the amount of saidemulsion is in the approximate range -160% of the dry weight of thefabric.

14. A dressing according to claim 13 in which the oil is petrolatum andthe fabric continuous filament rayon.

15. A sterilized dressing according to claim 14.

16. The method of making a non-sticking sterile surgical dressing whichcomprises preparing an aqueous emulsion of at least 5% of a petroleumoil based on the weight of fabric subsequently to be impregnated, and atleast 2% each of oil-soluble and water-soluble wetting agents, and atleast 4% Water, each based on the weight of the emulsion, impregnatingan open-mesh fabric with said emulsion, said fabric having regularlyspaced openings of average area in the approximate range 0.00015 to 0.04sq. in. each, the amount of said emulsion being in the approximate range100 to of the dry Weight of the fabric, sealing said dressing in acontainer having walls impermeable to micro-organisms, and heating saidcontainer and dressing for time and at temperature to sterilize saiddressing.

17. A dressing according to claim 5 having an absorbent layer adjacentsaid base fabric and contacting one side only of said base fabric,adapted to absorb fluid which passes through said base fabric from thewound.

18. A dressing according to claim 5 in which said emulsion contains amedicinal susceptible to deterioration at elevated temperatures.

19. A dressing according to claim 5 in which said oil is a polysiloxaneoil.

References Cited in the tile of this patent UNITED STATES PATENTS2,168,286 Eustis et al. Aug. 1, 1939 2,349,152 Feinstone May 16, 19442,711,168 Brickman et a1 June 21, 1955 FOREIGN PATENTS 158,613 GreatBritain Jan. 31, 1921

1. A SURGICAL DRESSING COMPRISING AN OPEN MESH BASE FABRIC IMPREGNATEDWITH AN OIL COMPOSITION, AND FABRIC HAVING REGULARLY SPACED OPENINGS OFAVERAGE AREA IN THE APPROXIMATE RANGE 0.00015 TO 0.04 SQ. IN. EACH, SAIDOIL COMPOSITION COMPRISING AT LEAST 5% BY WEIGHT OF A BLAND NON-TOXICOIL BAED ON THE DRY WEIGHT OF FABRIC AND 2% OF WETTING AGENT BASED ONTHE COMPOSITION, THE AMOUNT OF SAID COMPOSITIN BEING IN THE APPROXIMATERANGE 20 TO 200% OF THE DRY WEIGHT OF THE FABRIC.